The oral effects of cigarette smoking have been well documented but the effects of cannabis smoke on the oral environment have been poorly documented. Three-hundred cannabis/tobacco/methaqualone smokers were examined. Two control groups consisting of 152 tobacco- and 189 non-smokers respectively were examined similarly. Health of the oral tissues and oral dryness was recorded. Lesions present included leukoedema, leukoplakia and numerous others. The only significant differences between lesions and conditions noted in cannabis users and controls occurred with respect to leukoedema, dry mouth and traumatic ulcer.